Download - Buccal Object
-
8/3/2019 Buccal Object
1/46
Tube-Shift Localization (Clark)
SLOB RuleSame Lingual Opposite Buccal
The SLOB rule is used to identify the buccal orlingual location of objects (impacted teeth, root
canals, etc.) in relation to a reference object
(usually a tooth). If the image of an object moves
mesially when the tubehead is moved mesially(same direction), the object is located on the
lingual. If the image of the object moves distally
when the tubehead moves mesially (opposite
direction), the object is located on the buccal.
-
8/3/2019 Buccal Object
2/46
For the SLOB rule to work, there must be
a change in the horizontal or vertical
angulation of the x-ray beam as the
tubehead is moved. This change in
angulation will alter the relationship
between the object of interest and the
reference object, allowing you to
determine the buccal or lingual location.
The closer the object to be localized is tothe reference object, the less the amount
of movement of the image of the object in
relation to the reference object.
-
8/3/2019 Buccal Object
3/46
In the diagram at right, the
tubehead is moved, but there is
no change in direction of the x-ray
beam, which results in no changein location of the object of interest
in relation to reference object
(see below). Moving the tubehead
without changing the beam
direction would often result in a
cone cut , depending on how far
the tubehead is moved (see below
right).
-
8/3/2019 Buccal Object
4/46
When using the SLOB rule, the direction of the beam
must be opposite to the way the tubehead is moved.
Horizontal Tube Shift: When the tubehead is moved
mesially, the beam must be directed more distally (from
the mesial). If the tubehead is moved distally, thedirection of the beam must be more towards the mesial
(from the distal).
Vertical Tube Shift: The SLOB rule also works for
movement of the tubehead in a vertical direction.Downward movement of the tubehead requires that the
beam be directed upward and when the tubehead is
moved upward, the beam must be directed downward.
-
8/3/2019 Buccal Object
5/46
Moving the tubehead mesially or
distally and changing the direction of
the x-ray beam (as described in
previous slide) will result in themovement of the object of interest on
the film in relation to the reference
object. In the diagram at right, the
tubehead is moved distally with the x-
ray beam directed more mesially (from
the distal). The object of interest,
located lingual to the first molar,
moves distally, in the same direction
as the tubehead movement.
-
8/3/2019 Buccal Object
6/46
incisors
canine
premolar
molar
Horizontal movement of the tubehead and x-ray beam
In moving from the incisor film to the canine film, the canine
film to the premolar film and the premolar film to the molar
film, the tubehead moves distally and the beam is directedmore mesially. There is not much change in angulation from
the premolar to the molar film; the normal situation would
be that the beam is directed slightly more from the distal (or
to the mesial) as the tubehead is moved distally for the
molar projection.
-
8/3/2019 Buccal Object
7/46
In the diagram at left, the
buccal (yellow) and lingual
(red) objects of interest are
superimposed on each other
because the beam is directedperpendicular to both of them
and they are in the same
relative position mesiodistally
and vertically. Both images arelocated above the second
molar.
mesial
distal
mesialdistal
Horizontal movement
-
8/3/2019 Buccal Object
8/46
In the diagram at left, the
tubehead is moved distallyand the beam is directed
mesially. On the radiograph,
the buccal object of interest
(yellow) moves mesially(opposite to tubehead
movement) in relation to the
second molar and the lingual
object of interest (red) moves
distally (same direction astubehead) in relation to the
second molar.
mesialdistal
mesial
distal
Horizontal movement
-
8/3/2019 Buccal Object
9/46
In the diagram at right, thetubehead is moved mesially
and the beam is directed
distally. On the radiograph, the
buccal object of interest
(yellow) moves distally
(opposite to tubehead
movement) in relation to the
second molar and the lingual
object of interest (red) movesmesially (same direction as
tubehead) in relation to the
second molar.
mesial
distal
mesialdistal
Horizontal movement
-
8/3/2019 Buccal Object
10/46
Maxillary PA
BW
Mandibular PA
Vertical movement of the tubehead and x-ray beam
In moving from the maxillary periapical to the bitewing
and from the bitewing to the mandibular periapical, the
tubehead moves down and the beam is redirected
upward (opposite direction; decreased vertical
angulation).
-
8/3/2019 Buccal Object
11/46
In the diagram at left, the
buccal (yellow) and lingual
(red) objects of interest are
superimposed on each other
because the beam is directedperpendicular to both of them
and they are in the same
relative position mesiodistally
and vertically. Both images are
superimposed over the
mandibular second premolar.
Vertical movement
-
8/3/2019 Buccal Object
12/46
In the diagram at left, thetubehead is moved upward
and the beam is directed
downward. On the radiograph,
the buccal object of interest
(yellow) moves down
(opposite to tubehead
movement) in relation to the
second premolar and the
lingual object of interest (red)moves up (same direction as
tubehead) in relation to the
second premolar.
Vertical movement
-
8/3/2019 Buccal Object
13/46
In the diagram at left, thetubehead is moved downward
and the beam is directed
upward. On the radiograph,
the buccal object of interest
(yellow) moves up (opposite
to tubehead movement) in
relation to the second
premolar and the lingual
object of interest (red) movesdown (same direction as
tubehead) in relation to the
second premolar.
Vertical movement
-
8/3/2019 Buccal Object
14/46
Usually when using the tube-shift method of
localization, two film are taken of the same areausing different beam angulations. However, this
localization technique will also work when
comparing films taken as part of a complete series
of radiographs. The only difficulty is determiningwhich way the beam was directed when
comparing the molar and premolar films. Usually
this can be done by comparing the relative
positions of anatomical structures (e.g., zygomatic
process in maxilla or mental foramen in mandible)or the angulation of the roots of the teeth.
(See following two slides).
-
8/3/2019 Buccal Object
15/46
For the films above, we know that the tubehead was moveddistally from the premolar to the molar film. The zygomatic
process (red arrows) is located at the distal aspect of the 2nd
molar on the premolar film and it is located over the distal
aspect of the 1st molar on the molar film. This indicates that
it moved mesially as the tubehead moved distally. We know
that the zygomatic process is buccal to the teeth and, using
the SLOB rule, it follows that the tubehead was directed
more mesially on the molar film (Buccal object moved
opposite to tubehead movement).
premolar molar
-
8/3/2019 Buccal Object
16/46
premolar molar
Another way of determining the change in the directionof the beam is to look at the angulation of the teeth. In
the premolar film, the roots of the teeth are angled
distally, indicating that the beam was directed distally
(from the mesial). In the molar film, the roots are more
upright or angled slightly mesially, indicating the beamwas directed more mesially (from the distal). Therefore,
the tubehead shifted distally and the beam was angled
in the opposite direction, allowing the use of the SLOB
rule (These films were taken from Slide 3 in the review
films to follow).
-
8/3/2019 Buccal Object
17/46
On the following slides, identify the buccal or
lingual location of the selected objects. Each
slide will be followed with a slide indicating the
correct response and a brief explanation.
-
8/3/2019 Buccal Object
18/46
Is the composite restoration on tooth # 8 (red arrow)
located on the buccal or lingual?
canine film incisor film1
-
8/3/2019 Buccal Object
19/46
The restoration is located on the buccal. The tubehead
moves mesially from the canine to the incisor film (x-ray
beam projected more distally) and the composite moves
distally, which is the opposite direction.
canine film incisor film1
-
8/3/2019 Buccal Object
20/46
canine filmpremolar film
The red arrow in the canine film is pointing to the gutta
percha in which canal of the maxillary first premolar?
2
-
8/3/2019 Buccal Object
21/46
canine filmpremolar film
The arrow identifies the lingual canal. The tubehead
moves mesially from the premolar to the canine film
(beam directed more distally) and the gutta percha
indicated by the arrow also moves mesially.
2
-
8/3/2019 Buccal Object
22/46
PID
lingual
buccal
When the tubehead is moved, with the beam angulationredirected in the opposite direction, the two canals, which
are initially superimposed (premolar periapical above) will
separate. The lingual canal (red arrow) will follow the
tubehead movement and the buccal canal (blue arrow) will
move in the opposite direction, as seen on the canine film.
-
8/3/2019 Buccal Object
23/46
Is the maxillary second
premolar displaced to the
buccal or the lingual?
premolar film molar film
premolar bitewing
3
-
8/3/2019 Buccal Object
24/46
premolar film molar film
premolar bitewing
The tubehead moves distally from the
premolar film to the molar film. The
second premolar also moves distally,
overlapping the first molar more in themolar film. In moving from the
premolar periapical to the bitewing,
the tubehead moves down and the
premolar also moves down. The
displacement is to the lingual.
3
-
8/3/2019 Buccal Object
25/46
incisor film canine film
Is the displaced incisor (arrow) located on the buccal or
the lingual?
4
-
8/3/2019 Buccal Object
26/46
incisor film canine film
The lateral incisor is displaced to the lingual. The
tubehead moves distally from the incisor to the canine
film. The lateral incisor also moves distally, covering
half the canine on the canine film.
4
-
8/3/2019 Buccal Object
27/46
canine film
premolar film
Is the radiopaque object identified by the arrow located
on the buccal or the lingual?
5
-
8/3/2019 Buccal Object
28/46
canine film
premolar film
Lingual. The tubehead moves mesially from the premolar
film to the canine film. The object also moves mesially,starting out distal to the first molar on the premolar film and
ending up mesial to the first molar on the canine film. This
object is apparently located toward the center of the palate
because of the extreme movement from distal to mesial on
the films.
5
-
8/3/2019 Buccal Object
29/46
6
The maxillary right lateral incisor is tilted out of position.
In which direction (buccal or lingual) is it tipped?
premolar film incisor film
-
8/3/2019 Buccal Object
30/46
6
The tubehead moves mesially from the premolar film to the
incisor film. The lateral incisor also moves mesially,
starting out overlying the canine on the premolar film and
ending up over the central incisor on the incisor film. Since
the lateral moves the same direction as the tubehead, it is
tipped lingually.
premolar film incisor film
-
8/3/2019 Buccal Object
31/46
incisor film canine film7
The maxillary left canine is impacted. Is it located more
to the buccal or the lingual?
-
8/3/2019 Buccal Object
32/46
canine filmincisor film 7
The tubehead moves distally from the incisor film to the
canine film. The impacted canine also moves distally,
starting out overlying # 9 on the incisor film and ending up
over the lateral incisor on the canine film. The impacted
tooth is located on the lingual (palatal).
-
8/3/2019 Buccal Object
33/46
premolar bitewing film
8
The amalgam restoration
indicated by the arrow islocated on the buccal or
the lingual?
premolar periapical film
-
8/3/2019 Buccal Object
34/46
8
The tubehead moves downfrom the premolar
periapical film to the
bitewing film. The
restoration also moves
down, starting out abovethe two occlusal
restorations (red arrows)
on the periapical film and
ending up overlapping the
occlusal restorations onthe bitewing film. The
restoration (black arrow) is
located on the lingual.
premolar bitewing film
premolar periapical film
-
8/3/2019 Buccal Object
35/46
premolar periapical film
premolar bitewing film
9
The mandibular second
premolar is tilted out of
position. In whichdirection (buccal or
lingual) is it tipped?
-
8/3/2019 Buccal Object
36/46
9
The tubehead moves
down from the premolar
bitewing film to the
periapical film. Thesecond premolar also
moves down, indicating
that it is lingually tipped.
premolar periapical film
premolar bitewing film
-
8/3/2019 Buccal Object
37/46
molar bitewing film
molar periapical film
10
The arrow points to a
retention pin. Is the
pin located in thebuccal or lingual
portion of the tooth?
-
8/3/2019 Buccal Object
38/46
10
The tubehead movesdown from the molar
bitewing film to the
periapical film. The
pin identified by the
arrows also movesdownward. Since the
movement of the pin
follows the direction
the tubehead was
moved, it is locatedtoward the lingual
aspect of the tooth.
molar bitewing film
molar periapical film
-
8/3/2019 Buccal Object
39/46
premolar film molar film
11
Does the arrow point to the mesiobuccal or mesiolingual
canal?
-
8/3/2019 Buccal Object
40/46
11
The tubehead moves distally from the premolar film to themolar film. The canal indicated by the arrow also moves
distally to align with the other canal, which moves mesially
(The canals have to move in opposite directions in order to
be superimposed on each other). The indicated canal
(arrow) is located mesiolingually.
premolar film molar film
-
8/3/2019 Buccal Object
41/46
molar bitewing film
molar periapical film
12
The amalgam particle
indicated by the arrows
is located bucally orlingually?
-
8/3/2019 Buccal Object
42/46
The tubehead moves down
from the bitewing film to the
mandibular periapical film.
The amalgam particle moves
upward (opposite direction),indicating that it is located
buccally.
12
molar bitewing film
molar periapical film
-
8/3/2019 Buccal Object
43/46
Is the restoration
indicated by the red
arrows located on thebuccal or lingual of the
first premolar?
canine periapical film
premolar periapical film
premolar bitewing film13
-
8/3/2019 Buccal Object
44/46
The tubehead moves distally from
the canine film to the premolar
periapical. The restoration moves
mesially. From the bitewing to themandibular premolar periapical, the
tubehead moves down and the
restoration moves up. The
restoration is located on the buccal
of # 21.canine periapical film
premolar periapical film
premolar bitewing film13
-
8/3/2019 Buccal Object
45/46
14
incisor film canine film
premolar film
The gutta percha root canal filling identified by the red
arrows is located in which canal?
-
8/3/2019 Buccal Object
46/46
14
incisor film canine film
premolar film
In moving from the incisor film to the canine film, and
then from the canine film to the premolar film, the
tubehead moves distally. The gutta percha (red arrow)
also moves distally in each case. Therefore, it is in the
lingual canal